That was the verdict of former Ireland midfielder Matt Holland following Sunday's 4-0 warm-up win over Georgia.
The Republic play host to the Faroe Islands in Group C on Friday and will be without striker Shane Long who, along with midfielder James McCarthy, is suspended.
Nottingham Forest's Simon Cox started the game against Georgia and found the net, but Holland believes Sammon has to be brought into the starting line-up.
"Against the Faroes, you are looking for a like-for-like replacement (for Long) and it's got to be Sammon," Holland told Sky Sports HD.
"He is someone who holds the ball up, runs the channels and has a great worktate. He doesn't have the same pace as Long and he's not going to run behind teams like Shane will do and into the channels.
"But terms of a like-for-like replacement, I'm guessing that's the way Trappatoni is going.
"Cox played Okay; he got himself a deserved goal but he's very similar to Keane."
Holland and fellow former Republic midfielder Jason McAteer were both full of praise for the strikers on Sunday, not least Keane.
The LA Galaxy man moved level with record holder Shay Given with his 125th international cap when he came on as a half-time substitute against Georgia.
Keane scored twice in 11 minutes and that proved to Holland that they need him more than anyone else - even against the Faroe Islands.
"We wondered how much he's got in his legs but we wouldn't want anyone else because he's such a clinical finisher," said Holland. "He's been a great servant to the country. He's always shown a desire to turn up and it's just a fantastic record.
"One hundred and twenty five caps and his 55th and 56th goals, he is just an amazing player."